porism

(ˈpɔːrɪzəm)

(Mathematics) a type of mathematical proposition considered by Euclid, the meaning of which is now obscure. It is thought to be a proposition affirming the possibility of finding such conditions as will render a certain problem indeterminate or capable of innumerable solutions

[C14: from Late Latin porisma, from Greek: deduction, from porizein to deduce, carry; related to Greek poros passage]

porismatic, porismatical adj

Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

porism

Rare. a kind of geometrical proposition of ancient Greek mathematics arising during the investigation of some other proposition either as a corollary or as a condition that will render a certain problem indeterminate. — porismatic, adj.

See also: Mathematics

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References in periodicals archive

Porism, that, when the center of the circle falls within the triangle, the angle ABC is less than a right angle; and when the center of the circle falls outside the triangle, the angle ABC is greater than a right angle.

Porism. From this it is manifest that policies that are fair are not efficient in an aligned society (ABC is obtuse-angled).

Euclidean fairness and efficiency

In this paper we will concentrate on the so-called Poncelet porism for this specific setting.

The rational cases correspond to Poncelet's porism, and any rational number, except for 1/2, is related to a closed polygon, either without or with self-intersections.

On the rotation index of bar billiards and Poncelet's porism

This is Pappus' porism, which was the inspiration of much of Maclaurin's work on loci, beginning in 1772 [5, p 40].

Optimization of the courses in geometry by the usage of Dynamic Geometry Software Sam

This paper is constructed as follows: first we define some terminologies such as Poncelet's traverse and Poncelet's porism in the second section.

Poncelet's traverse and porism. We define a Poncelet's traverse and a Poncelet's porism in the following definitions:

Some relations of Poncelet's porism for two ellipses

Wider use of broadband should help to make PCs less vulnerable to attack, according to UK-based consultancy Porism Ltd.

Increased use of broadband could make PCs safer, claims Porism

An online UK schools guide and directory has been enhanced through a project carried out by Porism Ltd, a web site developer.

Porism enhances the UK Good Schools Guide Web site